We can - but if we keep the analogy of grown things we can only grow stuff that has already been grown before and make only tiny changes. It's worth remembering that evolution has neither purpose nor direction. Even "adapting" is an aimless process, the changes are predictable only for very small adaptations. Major changes may lead to anything, including a "restart" (extinction event followed by something different).

So the model has its limitations for human projects where we don't want to have quite that propensity for surprising outcomes.